Method and apparatus for prefocusing lamps



n n n cRoss REFERENCE if EXAMlNER D. E. ELMENDQRF 2,136,237

METHOD AND APPARATUS FOR PREFOCUSING LAMPS Filed June Ell, 1937 r VJ ClIl/M TUBE Irwventor: Dur yea E. E lmendorf,

b ($44144 l iis Attorney.

Patented Nov. 8, 1938 PATENT OFFICE METHOD AND APPARATUS FOR IBEFOCUS- INGLAMP Duryca a. Elmendorl', Shaker Heights, Ohio,

signor to General Electric Company, a corporation of New York Application June :1, 1931, Serial No. 140,455

12. Claims. (01. 176-3) My invention relates to the manufacture of incandescent lamps and more particularly to a method and apparatus for automatically adjusting the bulb of a lamp with reference to the base 5 one portion thereof to accurately locate the filament in a predetermined position with respect to said base or portion thereof.- Heretofore, such adjustment has been made manually with the assistance of optical means for showing the posil tion of the filament and of mechanical means r 20 light beam projecting means. The said bulb is then moved about in the reflector to gradually increase the amount of light directed thereby onto a light-sensitive cell located some distance therefrom, until finally the reflected or redirected light concentrates on the light-sensitive cell and the filament is in the correct position. The specific procedure is to move the bulb axially in or out of the parabolic reflector in whichever direction causes an increase in the amount of light falling 30 on the photocell and to stop this movement when the light peak is reached and the light falling on .the cell begins to decrease. Following -this movement. the bulb is moved in a lateral direction in the reflector until motion is again stopped, where- 5 upon it is moved perpendicularly to the said lateral direction until stopped. This series of movements may not necessarily adjust the filamerit to the correct location and it is preferred that the same sequence of operations be'per- 40 formed a second or even a third time before the base or portion thereof is attached to the rest of the lamp and the operations are completed. A lens or other optical means may be provided to assist in directing the light from the reflector 45 onto the photocell.

Other features and advantages of my invention will be apparent from the detailed description which follows and from the accompanying drawing of one species thereof.

so In the drawing, Fig. l is a somewhat diagramwit filament II which is sealed therein and the base II which is already cemented to the bulb II, is adjusted automatically to a predetermined position with respect to the collar M which is subsequently united to the said base. a The collar I4 is of the type shown in Frech Patent 2,033,699, issued March 10, 1936, and is inserted in the holder It. At the time of insertion, the fingers it are pulled back and collar I4 is placed in a recess in the holder l5 and registers with pins (not shown) which enter into the locating holes il in said collar. The fingers I! are held out of position by manual operation of a foot pedal (not shown) which moves red It toward the collar ll, causingthe slide-plug It to I6 engage the end of fingers It and move them away from the recess in holder IS. The release of the foot pedal allows the fingers It to be moved inward into contact with the collar ll by the spring which surrounds the holder l5 and fingers I6 20 and pulls inward on said fingers. The lamp I0 is now placed in the apparatus, the base It thereof being passed through the aperture in the reflector 2| and inserted in the collar ll andin the central aperture in holder ii, the bulb H being brought against the suction cup 22. The opening in the collar I4 and the aperture in holder ii are slightly larger than the base I! in order to permit the adjustment of the lamp ill necessary to bring the filament I! to the correct location, the base I 3 and the bulb ll being supported by the suction cup 22. Before the adjustment takes place, the

filament l2, which is connected through leadingin wires to the shell and end contact of the base I3, is connected to a source of electricity (not shown) by the fingers 24 and 25 respectively. The fingers 24. and 25 are pivoted in an insulating por; tion of the holder i5 and are pressed against their respective base portions by the springs 26 and 21. In this instance, it is preferred that direct cur- 40 rent be applied to the filament l2 so that it is caused to emit a uniform amount of light.

As so far described, the filament I2 is located only approximately in the desired position. The correct position is determined by means connected to the lamp l0 through the suction cup 22 which causes the lamp ID to be moved in different directions in a regular order under the control of the photocell 28. In this case, the filament I2 is properly located with respect to the base collar I4 when the said filament I2 is located at a point behind the focus of the parabolic reflector 2! which causes substantially all of the light redirected thereby to fall on the lens 29. The lens 28 in turn redirects the light through the aperu ture in the screen ill onto the photocell 28. In some cases, and particularly when the smaller miniature incandescent lamps are being adjusted, it is more desirable that the filament l2 be properly located when it is at the focus of the reflector 2| and that the lens or lenses 2! be as large as the said reflector 2| so as to receive all the light therefrom. The screen 30 may be dispensed with if desired, since it is used only to shield the photocell from stray light and, in this case, to limit the exposure of the photocell 28 to an equal amount in all directions as said photocell 28 is much longer than wide.

The lamp III is adjusted back and forth in three directions during the operation of the apparatus, one adjustment being crosswise vertically in the reflector and being produced when the electric motor II is operated and the slide 32. to which the suction cup 22 is attached by the arm 33, is moved in the ways of block 34. Another adjustment is crosswise of said reflector and at 90 to the other movement (1. e., horizontally) when electric motor II is operated and the block ll is slid in the ways of block 36. In a third adiustment, the lamp is moved axially in and out of the reflector when the electric motor 31 is operated and block 36 is slid in the ways of the block SI. In each case, the electric motors 3|, 3!, 81 operate a screw 30 through a speed reducer 4| mounted directly thereon as a unit, and are flxedly mounted so-that the screw 39 causes the slide 32 and blocks 84 and 36 to be moved. Each of the motors 3|, 3!, I! is series wound with separate fleld windings for each direction of rotation.

The apparatus is placed in operation by momentarily closing the push button 4! (Fig. 2)

which connects the coil 42 of the relay 43 to line conductor 44 through wires 45 and 45' and cause: said relay 0 to operate. The coil 42 is is so that it engages a contact connected through lead 48, the armature 50 of a second relay Ii and leads I! and 45 to the coil 42. This circuit causes the relay 3 to remain "closed".

The principal function of the relay II is to connect the leads from the separate fleld windings of motor 3'! which are connected to the armatures 53 and 54 to the wires 55 and 58 which are attached to contacts engaged thereby leading to the reversing relay 51. At the particular instant illustrated, both coils 58 and 59 of the relay I! are not energized and the armature 60 which is connected to the line conductor 44 is in engagement with a contact connected to wire I. which causes one of the fleld windings of the motor 81 to be energized. The armature of the motor I! is connected to the line conductor 41 and the energized fleld winding causes it to turn in a direction which can be assumed to be moving the lamp l0 out toward the mouth of the reflector 2|. If this direction of movement increases the amount of light received by the photocell 28, the movement continues, but if the light is decreasing, the reversing relay 51 is actuated and the other fleld winding of the motor "is connected to the line conductor 44 causing it to turn in the opposite direction and the lamp I! to be moved toward the throat or apex of the reflector ii. The increase in light on the photocell 28 causes the vacuum tube amplifier 6| to increase the potential of the direct current applied .o the primary 2 of the transformer 63 I CROSS REFERENCE amass? whereas a decrease in light on the photocell 1| causes the potential applied to said primary 62 to decrease. If the fllament I2 .is lighted with alternating or modulated current, a rectifler and filter are preferably inserted between the amplifler I and the transformer 83 to prevent any fluctuation in the current applied to said transformer 03 other than that produced by movement of said fliamen't l2. With the decrease in potential in the primary 2 of the transformer 63, a positive potential is induced in the secondary 64 which causes the electron tube 65 to pass current and the reversing relay 51 to operate, thereby connecting the second fleld winding of the motor 31 to the line conductor 44. The transformer secondary N is connected to the grid of the electron tube 65 and, through the grid bias battery 86, to the indirectly heated cathode thereof which is also connected to the secondary SI of the transformer 68. The transformer 88 supplies the plate current to the electron tube 85 to which it is connected at the instant of operation through the coil SI and the contact engaged by the armature of the reversing relay 1. When the relay coil II is energized, the armatures N and Ill are shifted causing, first, the line conductor 44 to be connected to the second fleld winding of the motor 31 and, second, the other relay coil ll to be connected to the transformer ll instead of the first coil 58. The primary ll of the transformer 89 is connected directly to both line conductors 44 and I1 and the other secondary I2 is connected to the heater fllament of the electron tube 65.

In whatever direction the filament I2 is moved during which the light falling on the photocell II continues to increase, no change takes place until flnally the filament l2 passes through the location causing the most light to fall on the photocell 2| and the light begins to decrease. The gradual increase in the amount of light received by the photocell ll causes the primary 2 of the transformer 63 to continue to increase in positive potential and the secondaries N and 13 to increase in negative potential until finally the light begins to decrease, whereupon the. secondaries change from a relatively high negative to a positive potential. This potential change is much greater than the similar change taking place-with the incorrect movement at the start .of operations and causes the circuit controlled by the electron tube 65 to be operated and the relay 51 reversed as well as causing the circuit connected to the transformer secondary I2 and controlled by the electron tube 14 to be operated. The ends of the secondary II are connected to the resistance 15, the grid of the tube 14 and through the condenser 16 and the grid bias battery TI to the indirectly heated cathode of said tube H. The condenser 16 and resistance prevent the electron tube 14 from passing current when the first light change takes place and have values depending on the other apparatus used. The cathode of the electron tube H is also connected to the secondary 18 of the transformer 69 which is connected through the coil 19 of the control relay 80 to the plate of electron tube 14 and which provides the plate current therefor. The passage of current through the coil 19 of the relay 80 pulls the armature thereof, which is connected to the line conductor 44, into engagement momentarily with the lead connected to the armature ll of the relay ii. The armature ll is in engagement with a contact connected to the armature ll of relay 4! which in EXAMINER turn is in engagement with a contact connected by lead 83 to the coil 84 of relay The coil 84 is energized by the actuation of relay 5| since the circuit therethrough is completed by the lead 85 to the line conductor 41. Energization of the relay coil 84 moves the armatures of the relay 5|, causing armature 59 to be moved away from engagement with its associated contact and the circuit to the coil 42 of relay 43 to be broken.

With the coil 42 of the relay 43 not energized, the armatures 53 and 54 are out of engagement with their associated contacts and the circuits to the field windings of motor 31 are broken, causing no further adjustment; the armature 48 is shifted so that it engages a contact connected through lead 86 to the armature 81 of relay 88 and connects the line conductor 44 thereto; and armature 82 is shifted so that it breaks the described connection to the coil 84 of relay 5| and engages the contact connected through leads 45 and 89 to the coil 42 of relay 43. Once the armatures of relay 5| are shifted by the energlzation of the coil 84, a second circuit thereto is completed through the armature 98 of relay 88 which engages a contact connected through lead 9| to a contact engaged by the armature 92 of relay 5|. The armature 92 is connected to the line conductor 44 through leads 93 and 45' and causes the relay coil 84 to continue to be energized even though the circuit through relay 43 is broken at the same time. The function of the relay 5| is to connect the leads from the separate field windings of the motor 35 which are connected to the armatures 94 and 95 thereof to the leads 55 and 55 leading to the reversing relay 51 and the contacts engaged by said armatures '84 and 95.

The motor 35 is operated as in the previous instance in a direction which causes an increase in the amount of light falling on the photocell 28 and is stopped by the momentary actuation of control relay 80 when the maximum amount of light falls on said photocell 28. Actuation of relay 88 in this instance causes the line conductor 44, which is connected to the armature thereof, to be connected to the relay contact which is at this time connected through the armature 8| of relay 5|, acontact engaged thereby, and lead 95, to the coil 91 of the relay 88. These connections energize the coil 91 which is connected bythe leads 98 and 48 to the line conductor 41 and cause the armatures for the relay 88 to be shifted. A second circuit to the relay coil 91 is then completed so as to hold the armatures in this position during this third adjustment by the engagement of armature 81 with the contact connected to the coil 91. As previously described, the armature 81 is connected through the lead 85 and armature 48 of relay 43 to the line conductor 44. The said shifting of the armatures of relay 88 also causes the armature 98 to move away from the contact attached to conductor 9|, thereby breaking the circuit from said armature 90 to the coil 84 of relay 5| which permits the anmatures of said relay 5| to return to their former position. Armature 8| is moved from engagement with the contact connected to lead 95 and the first circuit to the relay coil 91 is broken. The armatures 99 and H are moved into engagement with contacts connected to the field windings of the motor 3| and serve to connect the said windings, through the leads |8| and I82 respectively,.to'the reversing relay 51.

As in the previous instances, the photocell 28 and mechanism connected thereto control the operation of the motor 3| so that the lamp I0 is finally brought to a position in which the filament |2 is in the correct location or relatively near thereto. In some instances, this operation should complete the operation of our apparatus, but it is preferred to have .the apparatus continue through the adjustments a second or even a third time to correct any misalignment. In either case, the operations are automatically repeated by the actuation of relay 80 when the motor 31 finally brings the lamp l0 into position. The relay 80 is operated only momentarily and causes-the coil 42 of relay 43 to be energized. The connection is made through the relay 80 to the armature 8| of relay 5| which in turn engages the contact connected to armature 82 of relay 43. The armature 82 engages the contact of the lead 89 which is connected to the coil 42 through lead 45. The energization of the coil 42 causes the armatures of the relay 43 to be shifted thereby causing the circuit to the coil 91 of relay 88 to be broken and the other operations already described to follow. The circuit to the coil 91 of relay 88 is broken by the movement of armature 48 of relay 43 away from the contact attached to conductor 88. The

adjustments following occur in very rapid order and the collar is then fastened, preferably by solder, to the base |3 before the lamp parts-are removed from the machine. corporated in my apparatus to cause operation thereof to be discontinued after a given length of grme or a number of cycles of operation, if deed. What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for accurately locating the filament of an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion, means located adjacent to said holder for supporting the said bulb with the filament at approximately the desired location, means for connecting the said filament to a source of current to cause it to emit light, means located adjacent to said holder for directing light emitted by said filament in a beam in a given direction, lightsensitive means located in the path of the said light beam when the filament is correctly located for receiving the whole of said light beam, and means controlled by said light-sensitive means for moving the said bulb with respect to said holder to cause the said light beam to concentrate on the said light-sensitive means whereby the said filament is located correctly with respect to the said base portion. Y

, 2. Apparatus .for accurately locating the filament of an incandescent lamp sealed within a bulb with respect 'to a portion of a base which comprises a holder for the said baseportion, means located adjacent the holder for supporting the said bulb with thefilament at approximately the desired location,'means for connecting the filament to a source of current to cause it to emit light, a parabolic reflector located adjacent to .said holder for directing light emitted by said filament in a beam in a given direction, light- .sensitive'n'ieans located in the path of the said light heard when the filament is correctly located for receiving the whole ofsaid light beam, and means controlled by said light-sensitive means for moving the said bulb with respect to said holder to cause the light beam to concentrate on ,the said light-sensitive means whereby the fila- .ment is located correctly -with respect to the said base portion.

,3. Apparatus for accurately locating the fila- A switch may be inment or an incandescent lamp sealed within a -bulbwithrespecttoaportionofabasewhich comprises a holder for the said base portion, means located adjacent to said holder for supporting the said bulb with the filament at approximately the desired location, means for connecting the filament to a source of current to cause it toemit light, means located adjacent to said holder for directing light emitted by the filament in a beam in a given direction, a lens located in the path of said light beam for concentrating said light beam, light-sensitive means located behind said lens in the path of the light beam when the filament is correctly located for receiving the whole of said light beam, and means controlled by said light-sensitive means for moving'the said bulb with respect to said holder to cause the light beam to concentrate on the said light-sensitive means whereby the filament is located correctly with respect to the said base portion.

4. Apparatus for accurately locating the filament of an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion, means located adiacent to said holder for supporting the bulb with the filament at approxi-. mately the desired location, means for connecting the filament to a source of current to cause it to emit light, means located adjacent to said holder for directing light emitted by the filament in a beam in a given direction, light-sensitive means located in the path of the said light beam when the filament is correctly located for receiving the whole 0! said light beam. a screen disposed between the said light-sensitive means and the holder having an aperture therein through which the light beam passes when the filament is correctly located, and means controlled by said light-sensitive means Ior moving the said bulb with respect to said holder to cause the light beam to concentrate on the said light-sensitive means whereby the filament is located correctly with respect to the said base portion.

5. Apparatus for accurately locating the filament oi an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion, means located adjacent to said holder for supporting the said bulb with the filament at approximately the desired location, means for connecting the filament to a source of current to cause it to emit light, means located adjacent to said holder for directing light emitted by the filament in a beam in a given direction, a photocell located in the path of the said light beam when the filament is correctly located for re ceiving the whole of said light beam, means for moving the said bulb with respect to said holder to cause the light beam to concentrate on said photocell, and control means connected to said last-named means and to said photocell for causing the movement of said bulb to take place in such directions as to cause the amount of light falling on the photocell to increase and for causing the movement to be discontinued when the whole of the beam ialls on said photocell.

8. Apparatus for accurately locating the filament of an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion, means located adjacent to said holder for supporting the said bulb with the filament at approximately the desired location, means tor connecting the filament to a source of current to sum-0's cause it to emit light, means located adjacentto said holder for directing light emitted by the filament in a beam in a given direction, a photocell located in the path 0! the said light beam when the'filament is correctly located for receiving the whole or said lightbeam, means for moving the said bulb axially back and forth in the direction 01 said light beam and in two directions at right angles to each other and transverse to said light beam, means connected to said lastnamed'means and to said photocell for causing the movement to take place in each 0! said directions so as to cause an increase in the amount of light railing on said photocell, and control means for discontinuing the movements in each direction when the amount or light ialling on the photocell begins to decrease whereby the filament is correctly located.

- '1. Apparatus for accurately locating the filament of an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion, means located adjacent to said holder for supporting the said bulb with the filament'at approximately the desired location, means ior connecting the. filament to a source 0! current to cause it to emit light, means located adjacent to said holder for directing l sht emitted by the filament in a beam in a given direction, a photocell located in the path of the said light beam when the filament is correctly located for receiving the whole of said light beam, means for moving the said bulb axially back and forth in the direction 0! said light beam and in two directions at right angles to each other and transverse to the light beam, a plurality of electric motors each connected to said moving means for causing adjustment thereof in one of said directions, means including a plurality of electrical relays for connecting each of said electric motors in turn to a source of current, a reversing relay connected to the electric motors and to the photocell for changing the electrical connections to and reversing the direction of motion or said electric motors when the amount of light falling on the photocell decreases, and control means connected to said photocell and to said electrical relays for causing said relays to be actuated to the electric motors to operate and the movement of the said bulb to take place and to cause discontinuation 01 each of said movements when further movement in each direction causes the amount of light falling on, the photocell to decrease whereby the filament is correctly located. 8. Apparatus for accurately locating the filament of an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion,

means located adjacent to said holder for supporting the said bulb with the filament at approximately the desired location, means for connecting the filament to a source of current to cause it to emit light, means located adjacent to said holder for directing light emitted by the filament in a beam in a given direction, a photo- 65 cell located in the path of the said light beam when the filament is correctly located for receiving the whole oi said light beam, means for moving the said bulb axially back and forth in the direction of said light beam and in two directions at right angles to each other and transverse to the light beam, a plurality of electric motors each connected to said moving means for causing adjustment thereof in one of said directions, means including a plurality of electrical operation thereof in turn, means connected to said last-named relay and to the photocell for causing said relay to be operated when the movement of the said bulb either back or forth causes -the amount of light received by the said photo cell to decrease and a considerable change in potential to occur in said photocell as the lilament reaches the correct location or as near thereto as the particular direction of movement permits.

9. Apparatus for accurately locating the filament of an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion, means located adjacent to said holder for supporting the said bulb with the filament at approximately the desired'location, means for connecting the filament to a source of current to cause it to emit light, a parabolic reflector located adjacent to said holder for directing light emitted by the filament in a beam in a given direction, a photocell located in the path of the said light beam when the filament is correctly located for receiving the whole of said light beam, means for moving the said bulb with respect to said holder to cause the light beam to concentrate on the photocell, and control means connected to said last-named means and to the photocell for causing the movement of the said bulb to take place in directions which cause the amount of light falling on the photocell to increase and for causing the movement to be discontinued when the whole of the beam falls on said photocell.

10. Apparatus for accurately locating the filament of an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion, means located adjacent to said holder for supporting the said bulb with the filament at approximately the desired location, means for con-- necting the filament to a source of current to cause it to emit light, a parabolic reflector located adjacent to said holder for directing light emitted by the filament in a beam in a given direction, a photocell located in the path of the said light beam when the filament is correctly located for receiving the whole of said light beam, a screen disposed between the photocell and the holder having an aperture therein through which the light beam passes when the filament is correctly located, means for moving the said bulb with respect to said holder to cause the light beam to concentrate on the photocell, and control means connected to said last-named means and to the photocell for causing the movement of the said bulb to take place in directions which cause the amount of light falling on the photocell to increase and for causing the movement to be discontinued when the whole of the beam falls on said photocell.

11. Apparatus for locating a light source in definite predetermined relation to a light-concentrating reflector comprising means for supporting said light source at approximately the desired location, means for connecting said light source to a source of electrical energy to cause said reflector to project a beam of light in a given direction, light-sensitive means located in the path of said light beam when said light source is correctly located, and mechanism controlled by said light-sensitive means for moving said light source with respect to said reflector to cause the said light-beam to concentrate on said lightsensitive means whereby the said light source is located correctly with respect to said reflector.

12. Apparatus for accurately locating the fllament of an incandescent lamp sealed within a bulb with respect to a portion of a base which comprises a holder for the said base portion, means located adjacent to said holder for supporting the said bulb with the filament at approximately the desired location, means for connecting the filament to a source of current to cause it to emit light, means located adjacent to said holder for directing light emitted by the filament in a beam in a given direction, a photocell located in the path of the said light beam when the filament is correctly located for receiving the whole of said light beam, means for moving the said bulb axially back and forth in the direction of said light beam and in two directions at right angles to each other and transverse to the light beam, a plurality of electric motors each connected to said moving means for causing adjustment thereof in one of said directions, means including a plurality of electrical relays for connecting each of said electric motors in turn to a source of current, an electron discharge tube, a reversing relay connected to said electric motors and to said photocell through said discharge tube for changing the electrical connections to and reversing the direction of motion of said electric motors when the amount of light falling on the photocell decreases, a control relay connected to one of said electrical-relays and therethrough to each of the other electrical relays for causing operation thereof in turn, means including a second electron discharge tube connected to said control relay and to the photocell for causing said relay to be operated when the movement of the said bulb either back or forth causes the amount of light received by the said photocell to decrease and a considerable change in potential to occur in said photocell as the filament reaches the correct location or as near thereto as the particular direction of movement permits.

DURYEA E. EIMENDORF. 

